1. Field
The present invention relates to integrated circuit component second level (package-to-board) interconnection. More specifically, the invention relates to an Land Grid Array (LGA) socket with smaller contact pitch as compared to known LGA sockets, and the method of fabricating and assembling the socket.
2. Discussion of Related Art
A component socket is employed to couple an integrated circuit package to a circuit board. Pin Grid Array (PGA) and Land Grid Array (LGA) packages require a component socket to be connected to a circuit board because PGA and LGA packages do not have solder balls at the bottom of the package to be soldered to a circuit board directly.
FIG. 1A shows the top view of a known LGA socket housing 100. Socket housing 100 includes contact carrier 121. FIG. 1B shows a perspective view of contact carrier 121 having a plurality of pockets 126. Pockets 126 house electrically conductive contacts 124. The upper portion of contact 124 connects with the lands of LGA package while the bottom portion of contact 124 is soldered to solder ball 128. Walls 122 of contact carrier 121 provide structural support to contacts 124 and prevent contacts 124 from touching each other. FIG. 1C illustrates the top view of four adjacent pockets 126 defined by walls 122 of contact carrier 121 (contacts 124 are not shown here). Walls 122 are illustrated to assume wall thickness 146. Contacts 124 housed within pockets 126 of pocket width 144 would define socket pitch 142.
As semiconductor devices are designed to pack more transistors in the silicon and more than one silicon chip on the package, the number of second level interconnects of the integrated circuit package grows tremendously. Package interconnect pitch reduction is required to avoid substantial increase in package size. However, historically, interconnect and socket pitches reductions have progressed slower than the increase of the number of interconnects. Pitch reduction of known LGA sockets, among other factors, is limited by walls 122 of contact carrier 121 and the void space consumed by pockets 126 of contact carrier 121.